Well-known for its emphasis on etiquette, the Victorian era saw a formal code for table manners established. Eating was seen as a somewhat bestial activity and the refined diner was expected to maintain a genteel distance from such grossness. It was during this period that the use of knives and forks became customary.
For children, dining codes operated in tandem with rules of deference to adults. They had to wait until last to be served, without displaying any eagerness or expectation of receiving a particular dish. Requesting any article of food was considered the worst kind of vulgarity; one had to wait until it was offered. Any discussion of food, whether complimentary or not, was also strictly taboo.
Diners had to keep their elbows tucked discreetly at their sides; eat neither too fast (a sign of gluttony) nor too slowly (a failure of appreciation); refrain from picking their teeth or breathing heavily; and, of course, never speak with their mouths full. An extract from a Victorian cookbook detailing proper table manners can be read here.